This application claims the priority of German patent 198 05 175.1-24, filed Feb. 10, 1998, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a process and a system for connecting at least two components, particularly body components of motor vehicles, wherein the first component has an under cut on a side facing the second component.
In the vehicle body construction of motor vehicles, according to a prior art known from practice, two components, particularly side members and cross members which abut with one another in a T-shape, are connected with one another by welding. However, these very customary welded connections have the disadvantage that very large weld seams are required for this purpose and the two parts to be connected with one another may become extremely warped because of the effect of heat. The dimensional accuracy of the whole vehicle body structure which is created by the connection of several components with one another can therefore not be raised to a very high level.
From German Patent Document DE-OS 1 811 010, a process is known for the mutual connection of two metal parts, which are provided on their abutting surfaces with mutually opposite recesses which expand toward the inside. When the metal parts are joined, these recesses form a cohesive hollow space. For connecting the two parts, heated metal is charged into this hollow space. This metal shrinks when cooling and thus pulls the metal parts together.
If the components are simple, the process described in that document may be suitable for a connection. However, because of the complicated structures occurring in the construction of vehicle bodies, it cannot be used appropriately.
U.S. Pat. No. 982,265 describes a process for joining a rod to a tube. Metal is poured into the tube and the rod is thus connected with the tube.
Furthermore, from U.S. Pat. No. 1,021,437, a connection is known for two tubes which is created by pouring liquid metal into the connection area of the two tubes which mutually abut in a T-shape.
It is an object of the present invention, to provide a process for connecting two components which represents a simple, secure connection, particularly in the vehicle body construction field and is suitable for a series production.
According to the invention, this and other objects have been achieved by providing a process for connecting a first motor vehicle component to a second motor vehicle component, the first component having an undercut on a side facing the second component, said process comprising the steps of: casting a connection piece onto said first component such that a portion of the connection piece extends into the undercut of the first component, a last-solidifying core area of said connection piece contracting to firmly connect the connection piece with the first component; and mounting the second component on the connection piece.
According to the invention, this and other objects have also been achieved by providing a process for connecting a motor vehicle body cross member to a motor vehicle body side member, said side member defining an undercut on a side facing said cross member, said process comprising: arranging a casting mold adjacent said undercut, said casting mold defining at least one mold space for forming a connection piece including a mounting area for mounting the cross member; flowing a molten material into said at least one mold space of the casting mold to form said connection piece, a portion of the molten material flowing into the undercut of the side member to form a connection between the connection piece and the side member after the molten material solidifies; and mounting said cross member on said mounting area of the connection piece.
According to the invention, this and other objects have also been achieved by providing a system for connecting at least two motor vehicle body members, comprising: a motor vehicle body cross member; a motor vehicle body side member defining an undercut on a side facing said cross member; a casting mold defining at least one mold space for forming a connection piece including a mounting area for mounting the cross member, said connection piece being cast onto said side member such that a portion of the connection piece extends into the undercut of the side member to connect the connection piece with the side member; and said cross member being mounted on said mounting area of the connection piece.
According to the invention, this and other objects have also been achieved by providing a connection of two motor vehicle body members, comprising: a motor vehicle body cross member; a motor vehicle body side member defining an undercut on a side facing said cross member; a connection piece including a mounting area for mounting the cross member, said connection piece being cast onto said side member such that a portion of the connection piece extends into the undercut of the side member to connect the connection piece with the side member; and said cross member being mounted on said mounting area of the connection piece.
Because of the last-solidifying core area, the connection piece contracts in the area around the undercut of the first component during the solidification such that a tensioning effect of very high forces occurs which, when the connection piece is completely solidified, leads to an extremely stable connection between the first component and the connection piece. The last-solidifying core area is determined by heat transfer factors which are known in the art. For example, the solidification front migrates as a function of the direction of heat loss from the outside to the inside. A variation in the surface-to-volume ratio of different areas of the connection piece affects solidification, since an area with a higher surface-to-volume ratio will solidify more quickly than an area with a lower surface-to-volume ratio. The solidification pattern may also be influenced with other measures, such as cooling specific areas to speed up solidification, or by insulating partial areas of the mold.
According to the invention, the second component is then mounted on the connection piece, whereby the two components are connected with one another in a simple manner. Thus, according to the selected shape of the connection piece, a linking of the second component to the first component takes place in an arbitrary manner.